What’s going on here?
The International Court of Justice (ICJ) convened in the Peace Palace at the Hague this week, to present an Advisory Opinion (AO) on the obligation of states (i.e. countries) to take actions on climate change.
Starting in a classroom in Fiji, students sat in a room discussing climate justice in 2019. The lecturer encouraged their students to engage in the extracurricular task of thinking about practical actions relating to climate justice. A crazy idea was proposed: asking the world’s highest court to produce an Advisory Opinion on the obligation of states to act on climate change.
Spurred on by the impacts these students saw in their home, in the low lying Pacific islands, a group of 27 students came together to form the Pacific Island Students Fighting Climate Change (PISFCC) and made their classroom idea a reality.
On July 23rd, 2025, the ICJ delivered a monumental opinion clearly outlining that states do have obligations under their climate agreements, but also under other areas of customary international law, relating to protecting our environment and the humans who reside on it now, and in future.
What does this mean?
You may have heard of the climate conferences (better known as “COPs”), biodiversity conferences, or the world health organisation. All of these contribute to a complex system of international agreements covering many different sectors and policy areas.
In the diagram below you can see a list of just the environmentally focussed agreements, nevermind other agreements covering human health, human rights, the list goes on!
As the list of international agreements grows, the scope of each agreement can become blurry as each agreement tries to complement prior existing agreements while preserving their unique scope or remit. This is a particular challenge when it comes to environmental and climate agreements, as climate change impacts so many aspects of the environment and vice versa.
This is where Advisory Opinions are helpful!
Advisory Opinions (AO) are legal instruments seeking to clarify specific questions of international law.
Though not legally binding, this climate AO has significant legal weight and has the ability to reinvigorate and shape a new era of climate responsibility.
Despite this, they still carry significant legal weight and moral authority. The advisory opinion on climate change in particular could reshape the landscape of climate responsibility.
Why should we care?
The AO provides legal clarity on the following:
- States can be held accountable for actions of private sector companies under their jurisdiction for failure in regulating or constraining the production or consumption of fossil fuels. States providing subsidies for fossil fuel production could be considered a breach of international law.
- Small islands states at risk of disappearing into the sea due to rising sea level legally shall retain statehood status (i.e. they will still be considered a country despite their land disappearing).
- The 1.5 degree goals set in the Paris Agreement is the legally binding climate goal – not the 2 degree, Plan B goal.
- Under rules of customary international law to prevent significant harm to other states, there is a duty for all countries to cooperate and this applies in the climate context. (I.e., even if countries like the U.S. are no longer signatories to the Paris Agreement, they still have a duty to partake in good faith action on climate change.)
- On a case by case basis, compensation for the impacts arising from climate change could be possible for those countries/persons most impacted by it.
At its core, this AO holds polluters accountable like never before on the international stage.
Courts across the world will look at the ICJ’s work and utilise this as the standard to which other courts should shape their future climate judgements on.
Be Curious!
- Fancy yourself a legal nerd? Read the full AO on the ICJ website.
- If the AO is too long, check out the Centre for International Environment Law’s debrief
- Watch this short video by InforMEA to learn more about the principles of international environmental law: https://www.youtube.com/watch?v=WPClK3qmSlE
- Learn more about the role of the International Court of Justice in this video by the United Nations
The post The world’s highest court of justice has spoken on climate change appeared first on Curious Earth.
